Ann: Higher Grade Core Confirmed at Cortadera, page-30

Was that in an email you received from the Cheshire Cat himself?

I've been reading that there are promising research developments in the heap leaching of sulphide ores which, if they come to fruition, could substantially change the economics of processing porphyry. Grade is not as critical in heap leaching. So that is interesting to hear that HCH is contemplating leaching low grade sulphide ore.

https://im-mining.com/2022/01/31/antofagasta-minerals-widens-potential-cuprochlor-process-primary-copper-sulphide-leaching-success-centinela/

Here's an overview of heap leaching written by the mining industry fashion guru Noel Ong ("Samso"):

do not advertise external links.au/companies/news/909015/heap-leaching-could-it-be-an-alternative-to-conventional-gold-extraction-909015.html

I can see where it might make sense to heap leach low grade copper sulphide ore if you have to strip it out anyway while digging your open pit mine to get to the higher grade ore. It probably doesn't cost a lot line some heap leach pads to stack it all up onto and let it leach away while you are processing the high grade oxide ore through an SX-EW circuit. Then when you are finished processing the oxide ore into copper plate you can come back and use the leached sulphide thorugh the SX-EW after the sulphide heaps have been sitting there for a couple of years. In the mean time, by the time you have built the flotation and concentrator circuit you should have reached the higher grade sulphide ore in the pit needed for that circuit.